Plant-based natural products have proven to be an important base for anti-viral drug development. Although less than one percent of the world's flora is extremely investigated for medicinal uses, 22-46 percent is classified as endangered species. Due to lack of sustainable use and conservation, genetic biodiversity of medicinal plants is continuously under the threat of extinction. Thus, there is an urgent need for identification of totally new, prototype anti-viral agents. A primary objective of this proposal is to identify potent bioactive compounds active against some elusive fatal viruses or those that represent a significant segment of the potential bioterrorism threat. Promising bioactive compounds may provide insight for the development of effective natural solutions to control some viruses as potential bioterrorism agents and new drugs to cure some fatal infectious diseases. This program addresses the "Healthy People 2010" focus area(s) of Immunization and Infectious Diseases. Measurable outcomes of the program will be in alignment with one (or more) of the following performance goal(s) for the National Center for Infectious Diseases: Protect Americans from Infectious diseases. Research objectives of the project are (1) Plant selection and acquisition; (2) Extraction and biological evaluation of extracts in In Vitro screening systems; (3) Isolation and structure elucidation of bioactive compounds; and (4) Bioactivity screening of selected pure isolates.